I would like to use the Fitt's Law to test some hypothesis. Anyway, it's the first time I use it, and I have some doubts.
Then aim of my experiment is to test if in a certain situation the Fitt's law is valid.
In this experiment, I have two conditions, differing in terms of difficulty.
Intuitively, I think I have to calculate the predicted values, using the Fitt's formula and verify if they are correlated with raw data.
Is it legit to study the Fitt's law with only two levels of difficulty?